Chronic obstructive pulmonary disease (COPD) is a major cause of death and disability in the United States. It has been estimated that COPD affects 10 to 20 percent of the adult population age 45 and older. COPD results in ventilatory impairments and symptoms of breathlessness (dyspnea) which result in an increasingly sedentary lifestyle, limited physical function and diminished quality of life. Additionally, COPD is more prevalent among older individuals who already exhibit declines in ventilatory function as a result of the aging process. This situation is further aggravated by the fact that older individuals have an increased ventilatory requirement for a given level of energy expenditure. The interaction among these factors frequently leads to further inactivity. This vicious cycle of physical inactivity leads to further deconditioning of the cardiovascular and musculoskeletal system along with a loss of physical function. The loss of physical functioning may have other adverse health effects such as increased risk for morbidity and death and a dramatically increased cost of health care. Short term studies with COPD patients indicate that exercise may result in improvement in disability. The primary aim of this study is to determine if an exercise intervention consisting of walking and upper extremity strengthening can be used to retard and/or rehabilitate physical disabilities as determined by measures of physical performance and self-reports of activities of daily living in a group of patients with COPD for up to two years. To accomplish this aim, 200 individuals with COPD will be randomized into an attention control group or an exercise intervention group. All subjects will be followed for a two year. period during which time measures of physical function will be assessed on a regular basis. If exercise is demonstrated to be beneficial over the long term, it will offer an important therapeutic intervention for a common and disabling disease of older people.